Investigators are evaluating the feasibility, safety and early efficacy of administering a commercially available dietary supplement containing potato-based resistant starch to subjects undergoing allogeneic SCT (stem cell transplant). The intervention will begin immediately prior to the conditioning phase and continue through day 100. Investigators hypothesize that short term administration of a resistant starch is capable of increasing levels of butyrate within the intestine that will reduce rates of acute GVHD (Graft-Versus-Host Disease).